- IR SPECTRAL STUDY AND SEMIEMPIRICAL CALCULATIONS OF THE THERMAL DECOMPOSITION PATHWAYS OF SOME SUBSTITUTED FURANDIONES
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Furan-2,3-diones, structurally related to ascorbic acid, show potential antitumour physiological activity.Previous studies on this class of compounds have been devoted to their reactivity and thermal decomposition in solutions.It was reported, that 5-(p-R-phenyl)furan-2,3-dione with R=H, CH3, Cl, Br undergoes thermal decomposition in benzene and methyl alcohol solutions with elimination of carbon monoxide, the reaction product being able to react further to afford stable products.On another side, previous studies on the photochemical decomposition of these compounds in an Ar matrix at 15 K, in a KBr matrix and in solution have demonstrated the elimination of carbon dioxide as being the first reaction step.The reaction intermediates, as evidenced by Fourier Transform IR spectrometry, are either a ketene and/or cyclopropenone.
- Aycard, Jean-Pierre,Bodot, Hubert,Hillebrand, Mihaela,N'Guessan, Thomas Y.,Hnach, Mochamed,et al.
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p. 686 - 695
(2007/10/02)
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- Flash vacuum pyrolysis of 2-diazo-8-oxabicyclo[3.2.1]oct-6-en-3-ones. A new method for the preparation of propadienones
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When diazoketones 3a and 3b are pyrolysed at 430°C and 10-4 torr, they undergo loss of N2 followed by Wolff rearrangement and loss of furan by retro Diels-Alder reaction to yield the desired propadienones 1(a,b). If argon is added to the pyrolysate mixture, these reactive compounds can be trapped under matrix isolation conditions at 22 K and observed by FTIR. Upon photolysis, 1b yields carbon monoxide and 2-butyne.
- Brahms,Dailey
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p. 1381 - 1384
(2007/10/02)
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- Ionized ethylidene ketene and its homologue methylene ketene
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The gas phase pyrolyses of crotonic and acrylic-trifluoroacetic anhydrides were shown to yield ethylidene ketene and methylene ketene , respectively.The former was identified via the collisional activation mass spectrum of its molecular ion.The ionization energies of the two ketenes, 8.68 and 9.12 +/- 0.05 eV respectively, measured using energy selected electrons, lead to 215 and 233 kcal mol-1 for their ionic heats of formation.
- Terlouw, Johan K.,Holmes, John L.,Lossing, F. P.
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p. 1722 - 1724
(2007/10/02)
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